1. Technical field
The present invention relates to a method for forming a diamond-like carbon (DLC) film.
2. Related Art
DLC has high hardness, superior low friction, abrasion resistance, insulation, corrosion resistance, gas barrier property, infrared transparency and biocompatibility, and is used as a coating film in various fields.
For example, forming a DLC film on polytetrafluoroethylene (PTFE), which is a polymeric material widely used in the semiconductor industry and the like due to its excellent chemical resistance, can increase its material properties.
In medical fields, forming a DLC film on an artificial blood vessel made of PTFE or a stent made of a metallic material such as stainless steel (SUS316), nitinol (NiTi) and titanium (Ti) can improve its biocompatibility and antithrombogenicity.
DLC films are utilized in a wide variety of other fields, e.g., in machine components, cutting tools, dies, optical components, medical equipment and decoration goods.
The DLC coating can be formed by, for example, a chemical vapor deposition (CVD) method. However, the adhesion strength of the DLC film relative to polymeric materials and metallic materials is low, so it has easily peeled off from the materials. In light of such circumstances, a technique for preventing peeling of the DLC film has been proposed, in which a DLC film is formed after forming a carbon intermediate layer on a surface of a polymeric material (see, for example, JP2005-2377 A).
However, as the technique disclosed in patent document 1 involves providing the carbon intermediate layer, it makes the treatment process more complicated.